1. Field of the Invention
Aspects of the present invention relate to a negative electrode for a rechargeable lithium battery and a rechargeable lithium battery including the same. More particularly, aspects of the present invention relate to a negative electrode for a rechargeable lithium battery that improves cell characteristics by inhibiting volume change and stress due to active material particle bombardments during charge and discharge, and a rechargeable lithium battery including the same.
2. Description of the Related Art
Lithium rechargeable batteries have become popular as power sources of small portable electronic devices. A lithium rechargeable battery uses an organic electrolyte solution and thereby has a discharge voltage that is twice as high as a conventional battery using an alkali aqueous solution. Accordingly, the lithium rechargeable battery has a high energy density.
For a positive active material of a rechargeable lithium battery, lithium-transition element composite oxides being capable of intercalating lithium, such as LiCoO2, LiMn2O4, LiNiO2, LiNi1-xCoxO2 (0<x<1), LiMnO2, and so on, have been used.
For a negative active material of a rechargeable lithium battery, various carbon-based materials such as artificial graphite, natural graphite, and hard carbon, which can intercalate and deintercalate lithium ions, have been used. Graphite increases discharge voltages and energy density of a battery because graphite has a low discharge potential of −0.2V compared to lithium. A battery using graphite as a negative active material has a high average discharge potential of 3.6V and an excellent energy density. Furthermore, graphite is most commonly used among the aforementioned carbon-based materials since graphite guarantees a better cycle life for a battery due to its outstanding reversibility. However, a graphite active material typically has a low density and consequently a low capacity in terms of energy density per unit volume when used as a negative active material. Further, the use of graphite involves some dangers such as explosion or combustion when a battery is misused or overcharged and the like, because graphite is likely to react with an organic electrolyte at a high discharge voltage.
In order to solve these problems, much research on oxide negative electrodes including tin oxide, or lithium vanadium oxide, has recently been carried out. However, such an oxide negative electrode does not show sufficient battery performance and therefore there has been a great deal of further research into oxide negative materials.